> $ dmesg | grep PLEX
> acd0: DVDR <PLEXTOR DVDR PX-708A> at ata1-master PIO4
^^^^ This must be the
culprit for at least inadequate performance. Try to
echo 'hw.ata.atapi_dma="1"' >> /boot/loader.conf
and reboot. I'll comment on other things later. Meanwhile see if it 6/8x
recording performs as expected with DMA on and report back. A.